Wear-compensating high efficiency gear pump



April 25, 1967 O, ECKERLE 3,315,609

WEAR-COMPENSATING HIGH EFFICIENCY GEAR PUMP Filed Aug. 25, 1966 4 Sheets-Sheet l K [O 8 D L 6 l3 l4 g Z? FIG. I

32 I 34 37 35 F/G. 2

L A? INVE'NTOR OTTO ECKERLE A ril 25, 1967 o. ECKERLE 3,315,609

TING HIGH EN Filed Aug. 25, 1966 4 Sheets-Sheet 2 IN VE NTOR.

OTTO ECKERLE ATTORNEY.

April 25, 1967 o. cKERLE" 3,315,609

WEAR'COMPENSATING HIGH EFFICIENCY GEAR PUMP Filed Aug. 25, 1966' r 4 Sheets-Sheet 5 OTTO ECKERLE ATTORNEY.

A ril 25, 1967 o. ECKERLE 3,315,509

WEAR-COMPENSATING HIGH EFFICIENCY GEAR PUMP Filed Aug. 25, 1966 4 Sheets-Sheet 4- as o OTTO ECKERLE BY ATTORN Y.

United States Patent P 3,315,609 WEAR-COMPENSATING HIGH EFFICIENCY GEAR PUM'P Otto Eckerle, Am Bergwald 3, Malsch,

Kreis Karlsruhe, Germany Filed Aug. 25, 1966, Ser. No. 575,111 Claims priority, application Germany, Aug. 31, 1965, E 30,008 11 Claims. (Cl. 103-126) The present application is a continuation-in-part of US. patent application, Serial No. 574,340, filed August 23, 1966, for: Wear-Compensating High Efliciency Gear Pump and the priority date to which said application is entitled is claimed here for all subject matter common therewith.

The present invention relates to geared pumps having a ring gear with internal teeth and a pinion with external teeth meshing with the internal teeth of the ring gear, as well as a crescent-shaped filling piece between the ring gear and the pinion.

The invention concerns the problem of constructing such pumps so that the load due to the pressure in the pressure chamber on the parts forming the pressure chamber, such as ring gear, pinion, filling piece, and axial gaskets, is compensated. In accordance with the present invention, the load is slightly overcompensated so that minor forces of the opposite direction keep the parts of the pressure chamber in sealing contact with one another, even when, with passing time, the effects of wear and tear become apparent on the individual parts.

Pumps of the above-described construction are known wherein the ring gear bearing, particularly critical on account of the large circumference and the high sliding speed, is constructed to be a hydrostatic, balanced bearing. It has furthermore been suggested to provide this hydrostatic bearing for the hollow wheel with a compensating piston, and to press the entire hollow wheel against a freely movably suspended filling piece and thus to press the latter against the pinion shaft. Thereby, the formation of gaps between the hollow wheel, the filling piece and the pinion, arising from wear-and tear, was to be avoided. The formation of such gaps would decrease the degree of efficiency of the pump.

However, it has become evident that under some conditions these measures are still not sufficient for operating such pumps over a long lifetime and at high operating pressures, since the bearing of the pinion shaft, provided in these pumps in the form of antifriction bearings or ordinary sliding bearings, stands up under such conditions only to a limited degree.

It is, therefore, the object of the present invention to construct pumps of the above-mentioned type in such a manner that the mounting of the pinion shaft maintains operation, practically independently of the selected operating pressure for a substantially longer lifetime and at least at equally good efliciencies.

Furthermore, it is another object of the present invention to decisively improve the entire efliciency of such pumps.

In order to achieve these objects according to the invention, the pinion shaft is mounted in hydrostatic bearings provided with balancing areas and the shaft cooperates with a likewise hydrostatically mounted ring gear and a filling piece. The filling piece is mounted so as to be displaceable, pivotable, and rotatable about its longitudinal axis. To this end, the mounting of the pinion shaft is effected by means of bearing plates provided with a balancing area. These plates are provided with sealing rings just a short distance before their front faces, as well as with a recess situated between these two sealing rings. This recess is connected, via a bore, with the 3,3 i5,60'9 Patented Apr. 25, 1967 chamber of an axial pressure piston and thence with the pressure chamber of the pump.

Thereby, the forces acting on the pinion shaft are balanced down to a small residual amount, so that the fluid pressure produced by the pump has practically no influence on the life of the pinion shaft bearing. At the same time, the mechanical degree of efiiciency is increased by a considerable amount.

In a further development of the invention, compensating pistons can additionally be arranged in the bearing plates. These pistons are provided with a balancing area carrying the pinion shaft and push the pinion shaft against the load effective thereon, toward the ring gear into mesh therewith and into sealing contact against the filling piece.

To this end, the filling piece is suspended such that it is displaceable, pivotable, and rotatable about its longitudinal axis.

In another development of the invention, the fastening pin serving for mounting the filling piece is mounted on both sides in compensating pistons in bearing plates. The pistons consequently press the floating filling piece against the ring gear and the pinion. For this purpose, the filling piece proper is pivotable on its fastening pin.

In a further development of the invention, the pinion and the ring gear are pressed, in a floating manner, with the aid of balanced compensating pistons, against the filling piece which is, in turn, suspended to be ivotable and rotatable about its longitudinal axis.

Furthermore, it is also possible, in a conventional manner, to mount the pinion shaft in a hydrostatic bearing provided with a balancing area, and to press the ring gear, with the aid of a balanced compensating piston, in a floating manner against the filling piece. The filling piece is hung to be displaceable, as well as pivotable and rotatable about its longitudinal axis. The filling piece is, in turn, pressed against the pinion shaft.

In all of the above-described cases, a complete balancing of the forces upon the parts is achieved, which parts are in floating engagement with one another; also, deleterious friction at their bearing surfaces is avoided, a sealing engagement of all parts forming the pump chamber is obtained, and an optimum mechanical degree of efiiciency of the entire pump is attained.

In a further embodiment of the invention, the fastening pin serving for mounting the filling piece is mounted at both ends in a compensating piston. This piston is arranged in a bore of the bearing plates running past the pinion shaft. One end of this compensating piston is connected with the pressure chambers of the pump via the recess between the two sealing rings of the bearing plate, while the other side of the compensating piston is under the oppositely directed force of a compression spring. The compensating piston is furthermore provided on this side with a friction-clutch coupling permitting only a short stroke in the direction of the force of the spring. Thereby, it is avoided that the filling piece presses against the gears during pressureless operation, or when the operation of the pumps is being initiated. Thus, the pump cannot be locked on account of an overly high sealing pressure of the filling piece against the gears.

In order to avoid the influence of the forces, effective externally upon the drive shaft, upon the hydrostatic bearing of the pinion shaft, a further development of the invention separates the pinion shaft proper, with its two bearing trunnions, from the drive shaft which is accessible from the outside. This is done by a coupling between the two shafts. The portion remaining as the drive shaft is, for this purpose, mounted in the lid by itself and sealed off toward the outside.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same shaft.

' the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof and wherein:

FIGURE 1 is a cross section through an embodiment of the invention.

FIGURE 2 is a longitudinal section through this pump along line IIII in FIGURE 1. Y

FIGURE 3 is a cross section along line III-III of FIGURE 2.

FIGURE 4 is a cross section of a modification of the embodiment of FIGURES l-3 along line IV-1V of FIGURE 2.

FIGURE 5 is a cross section through another embodiment of the pump.

FIGURE 6' shows a cross section through a further embodiment of the pump, at a similar place to that shown in FIGURE 3.

FIGURE 7 is a cross section through the pump of FIG- URE 6, similar to the cross section of FIGURE 4.

FIGURE 8 shows a further embodiment of the pump according to the invention, in a longitudinal section, the gears and thebearing plates not being in sectional view.

The pump illustrated in FIGURE 1 has a housing 1 with a connecting lid 2 on the vacuum side and a connecting lid 3 on the pressure side. The pressure chamber D of the pump is formed by the ring gear 4, the pinion 5, the control piston 6 provided with a balancing area 7, and the filling piece 8 hung on a slightly balled fastening pin 10 in a slot 9. The control piston 6 is fixedly connected, via pins 11, to the pressure connecting lid 3, and its pressure channel 12 is sealingly connected, via a seal 13, with the pressure connection 14.

The longitudinal section of this pump, according to FIGURE 2, shows the twobearing plates and 21', each with a compensating piston 21 provided with a compensating area 22 and a pressure area 23. The pressure area is sealed by a seal 24. In a bore 25 of each compensating piston, a spring 26 is provided, acting even in the case of pressureless operation of the pump. These springs press the compensating pistons respectively against the bearing trunnions 27 and 28 of the pinion shaft. A short distance before the two'faces of the bearing plates, gasket rings 29 and 30 are provided. A recess 31 between both sealing rings is in communication with the pressure area 34 of the axial pressure piston 35 via two bores 32 and 33.

FIGURE 3 shows a cross section through bearing plate 20 and the compensating piston 21 in a bore 36, which is approximately aligned through the center of the pinion The fastening pin 10, serving for mounting the filling piece, is fixedly inserted in the bearing plate 20. The recess 31 is in communication with pressure area 23 of the compensating piston, on the one hand, and via the bore 32, with the pressure chamber of the pump, on the other hand. The fastening pin 10 is extended through the bearing plate, and projects into a recess of the housing, thus securing the bearing plate 20 against rotation within the housing. This recess is not shown.

FIGURE 4 exposes a face of the bearing plate 20. In this modifications of FIGURES 13, pin 10 is not fixed in the bearing plate 20. Furthermore, the filling piece is pivoted about pin .10 and slot 9 is absent. In an elongated recess 40, extending approximately at right angles to the effective direction of the compensating piston 21, a slide ring 41 is provided receiving the fastening pin 10.

A further pin 42 serves for fixing the bearing plate'20. V

The plate has a recess 43 wherein an axial pressure piston 44 is provided. This piston has a flange and two equalizing slots 46 and in communication with the teeth of the ring gear. Both equalizing slots emanate from a bore 47, which runs to the pressure area 34 provided behind the pressure piston. I

In the pump illustrated in a cross-sectional view in FIGURE 5, the ring gear and the pinion shaft are pressed via compensating pistons, against the fixedly hung filling piece. The mounting of the ring gear 4, in turn, is effected via a control piston 50 provided with a balancing area 51. Two pressure pistons 52, 53 act on this control piston. The pressure pistons are provided in the pressure connection lid 54 and have seals 55. They are under the force of springs 56.

Compensating piston 21, provided with a balancing area 22, acts on the pinion shaft 5. A compression spring 26 urges this piston toward the shaft. The arrangement and construction of the entire bearing plate correspond to the embodiment illustrated in FIGURE 3. The slightly spherical fastening pin 10 for the filling piece is immovably inserted in the bearing plates, an additional fastening bolt 57 is placed in the same way.

In the pump embodiment shown in FIGURE 6, the pinion shaft 5 is mounted in a stationary manner and is radially relieved by a balancing area 60. The balancing area is loaded by fluid from the pump pressure chamber entering via a bore 61 communicating with the recess 31. A compensating piston 64 is provided in a radial bore 62 in the axial plate 63. The bore 62 extends past the hearing of the pinion shaft. The piston is in communication with the pressure chamber of the pump via the recess 31 and is also under the force of compression spring 65. The compression spring rests on two pins 66 and 67. The pin 66 positioned closer to the sealing plug 68 and a disk 69 act upon the trunnion 70 of the compensating piston, in the manner of a friction coupling, so that the compensating piston can execute only a short stroke under motivation by the spring when the pump is without pressure. Furthermore, the compensating piston has a bore wherein the fastening pin 10 for the filling piece is received.

FIGURE 7 shows in cross section more details of the pump of FIGURE 6. FIGURE 7 corresponds approximately to the cross section of FIGURE 4. The axial plate has an elongated perforation 76 wherein the pin 10 for the filling piece is guided. This guide is effective 7 at the same time as a bar to the rotary displacement of the compensating piston 64. The axial plate is furthermore secured against rotation by means of a pin 77inserted in the housing. Two grooves 78, extending through the bearing bore of the pinion shaft, bound the balancing area 60 formed in the bore. 'The axial plate is furthermore provided with arecess 43 wherein an axial pressure piston 44 is provided, having the above-described equalizing grooves and a channel tothe pressure area.

FIGURE 8 shows a difierent solution for-the pump of the present invention, with-reference to the embodiment shown and described in connection with FIGURES 6 and 7. For mounting the drive shaft 81, two ball bearings 83 are provided in the pump lid 80. The drive shaft 81 is provided, at its end facing the pinionshaft 84, with a key 85 engaging in a slot of the coupling disk 86.- The disk also has'a key'87. The two keys 8 5 and 87 are offset 7 with respect to each other by 90, so that there is formed a coupling which absorbs a parallel displacement, aswell as an angular displacement. w

The above-described figures are only examples for utilizing the present invention. The claimed solutions can, of course,'be employed for solving the same problems also in case of geared motors.

The divided pump shaft illustrated in FIGURE 8, which shaft is connected via -a coupling can be employed also in all other illustrated embodiments.

. All combinations of the subject matters of the present invention with those of the parent application Ser. No.

chosen for the purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention set forth in the appended claim-s.

I claim:

1. A wear compensating high efliciency gear pump for pumping fluid, comprising: a sealed housing; a pinion shaft laterally displaceably arranged through the housing; a pinion gear fixedly mounted coaxially on said drive shaft; a ring gear having internal teeth of a shape and spacing permitting meshing of its teeth with the teeth of said pinion gear; said ring gear having a pitch circle substantially larger than that of said pinion gear and surrounding said pinion within said housing; a filling piece situated between said pinion gear and said ring gear; said piece shaped for sealing engagement with the tips of the teeth of the gears when the gears are in mesh; said piece mounted pivotably about an axis parallel to said pinion shaft, displaceably substantially radially from said pinion shaft, and fixedly relative to rotation with said pinion shaft; pinion fluid pressure bearing means to urge said pinion into mesh with said ring gear, thereby forming a meshing zone, and into engagement said filling piece; ring gear fluid pressure bearing means to reduce the hearing force of said ring gear on said housing; sealing means to seal laterally a pressure chamber bounded peripherally by the gears and the filling piece before the meshing zone; fluid inlet means from with out the housing to the chamber bounded peripherally by the gears and the filling piece after the meshing zone; and fluid outlet means from the pressure chamber.

2. A gear pump as claimed in claim 1, said pinion fluid pressure bearing means and said ring gear fluid pressure bearing means pushing respectively the pinion and the ring gear against the filling piece, said pinion fluid pressure bearing means and said ring gear fluid pressure bearing means both including piston means exerting forces exceeding loads on respectively the pinion and the ring gear.

3. A gear pump as claimed in claim 1, further comprising a drive shaft mounted with one end in said housing, a coupling connected to the end of said drive shaft in said housing, said coupling connected to said pinion shaft.

4. A gear pump as claimed in claim 1, said pinion fluid pressure bearing means including at least one piston pushable against said pinion shaft under fluid pressure.

5. A gear pump as claimed in claim 4, further comprising bearing plates fixedly situated within said housing about said pinion shaft on both sides of said pinion, the pistons of said pinion fluid pressure bearing means situated within at least one of said bearing plates and pushable in at least one plane radial to said pinion shaft.

6. A gear pump as claimed in claim 5, said sealing means including recesses laterally from said pressure chamber in said bearing plates, said recesses having bores substantially parallel to the pinion shaft, conduit means to bring fluid from the pressurechamber into the recesses, pistons in said recesses movable by said fluid from the pressure chamber, and sealing flanges on said pistons formed for sealing engagement with the lateral surfaces of the gears and filling piece adjacent said pressure chamber.

7. A gear pump as claimed in claim 5, further comprising sealing rings between the housing and the bearing plates adjacent the faces of said bearing plates, said bearing plates each having a peripheral recess situated between their sealing rings, each recess being in communication with said pressure chamber.

8. A gear pump as claimed in claim 1, further comprising compensating piston means to hold the filling piece in engagement with the gears under a force larger than that exerted on the filling piece by fluid in the pressure chamber.

9. A gear pump as claimed in claim 8, further comprising bearing plates fixedly situated within said housing about said pinion shaft on both sides of said pinion, said compensating piston means including two boresin said bearing plates, there being one bore in each of said bearing plates on each side of said pinion, a compensating piston in each bore, and a means to connect the pressure chamber with each bore to supply pressurized fluid to operate said pistons, said bores being parallel and extending transversely past the pinion shaft, said filling piece mounted on a pin extending parallel to said pinion shaft, said pin mounted at each end in one of said pistons.

-10. A gear pump as claimed in claim 9, further comprising two springs, each mounted to a separate piston and opposing movement thereof away from pressurized fluid supplied by said means to connect.

11. A gear pump as claimed in claim 10, further comprising friction means to limit the stroke of said springs.

References Cited by the Examiner UNITED STATES PATENTS 1,604,802 10/ 1926 Brenzinger 103-126 1,646,615 10/ 1927 Furness 103126 2,482,713 9/1949 Jones 103126 2,504,230 4/1950 Smith 230143 2,915,982 12/1959 Crandall 103126 3,034,446 5/1962 Brundage 103126 3,053,192 9/1962 Nonnenmacher 103-126. 3,136,261 6/1964 Eckerle et al. 103126 3,265,005 8/1966 Ringgenberg 103-426 3,270,679 9/1966 Sand et a1 103-126 FOREIGN PATENTS 551,485 6/1932 Germany.

DONLEY J. STOCKING, Primary Examiner. W. I GOODLIN, Assistant Examiner. 

1. A WEAR COMPENSATING HIGH EFFICIENCY GEAR PUMP FOR PUMPING FLUID, COMPRISING: A SEALED HOUSING; A PINION SHAFT LATERALLY DISPLACEABLY ARRANGED THROUGH THE HOUSING; A PINION GEAR FIXEDLY MOUNTED COAXIALLY ON SAID DRIVE SHAFT; A RING GEAR HAVING INTERNAL TEETH OF A SHAPE AND SPACING PERMITTING MESHING OF ITS TEETH WITH THE TEETH OF SAID PINION GEAR; SAID RING GEAR HAVING A PITCH CIRCLE SUBSTANTIALLY LARGER THAN THAT OF SAID PINION GEAR AND SURROUNDING SAID PINION WITHIN SAID HOUSING; A FILLING PIECE SITUATED BETWEEN SAID PINION GEAR AND SAID RING GEAR; AND PIECE SHAPED FOR SEALING ENGAGEMENT WITH THE TIPS OF THE TEETH OF THE GEARS WHEN THE GEARS ARE IN MESH; SAID PIECE MOUNTED PIVOTABLY ABOUT AN AXIS PARALLEL TO SAID PINION SHAFT, DISPLACEABLY SUBSTANTIALLY RADIALLY FROM SAID PINION SHAFT, AND FIXEDLY RELATIVE TO ROTATION WITH SAID PINION SHAFT; PINION FLUID PRESSURE BEARING MEANS TO URGE SAID PINION INTO MESH WITH SAID RING GEAR, THEREBY FORMING A MESHING ZONE, AND INTO ENGAGEMENT SAID FILLING PIECE; RING GEAR FLUID PRESSURE BEARING MEANS TO REDUCE THE BEARING FORCE OF SAID RING GEAR ON SAID HOUSING; SEALING MEANS TO SEAL LATERALLY A PRESSURE CHAMBER BOUNDED PERIPHERALLY BY THE GEARS AND THE FILLING PIECE BEFORE THE MESHING ZONE; FLUID INLET MEANS FROM WITH OUT THE HOUSING TO THE CHAMBER BOUNDED PERIPHERALLY BY THE GEARS AND THE FILLING PIECE AFTER THE MESHING ZONE; AND FLUID OUTLET MEANS FROM THE PRESSURE CHAMBER. 